<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>BFC</title>
    <style>
        .box{
            /* width: 300px; */
            /* height: 300px; */
            background-color: pink;
            border: 2px solid greenyellow;
            /* float: left; */
            /* display: inline-block; */
            overflow: hidden;
        }
        .box1{
            width: 100px;
            height: 100px;
            background-color: beige;
            float: left;
        }
        .bottom{
            width: 200px;
            height: 200px;
            background: coral;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="box1"></div>
    </div>
    <div class="bottom"></div>
</body>
</html>